Recent advances in dentin bonding and the increased importance of esthetics in dental restorative preparations have accelerated the use of light activated resin composite materials as filling materials for both anterior and posterior restorations. However, despite improvements in materials and techniques, the placement of the resin composite remains technique sensitive and establishing firm and properly located interproximal contact using resin composite filling materials particularly for posterior restorations remains difficult to achieve. If adequate contact is not achieved after matrix removal, a space will occur with the adjacent tooth. Food impaction may result in decay formation and periodontal disease. The plasticity of resin composite materials prior to the application of light radiation for curing the material makes it difficult to contour the restoration and to establish contact with adjacent teeth. In addition, it is, at present, difficult to cure composite in the deeper recesses of a dental preparation. Moreover, currently available dental instruments do not make accurate contact mesially and distally to provide for adequate approximal contact during hardening and are unable to accommodate different size preparations. Commercially available devices are also unable to gauge or monitor the depth of the restoration or to assist in aligning the preparation with an adjacent tooth. For proper curing of the resin composite light must to able pass from the light curing source into the gingival floor area through the proximal box. Otherwise open margins, sensitivity and recurrent decay will develop. Accordingly, the dental instrument should facilitate the transmission of light into the gingival floor areas.